Security callback: selects which parameters are permitted including
sensible defaults based on bits of security.

The "parameters" which can be selected include: ciphersuites,
curves, key sizes, certificate signature algorithms, supported
signature algorithms, DH parameters, SSL/TLS version, session tickets
and compression.

In some cases prohibiting the use of a parameters will mean they are
not advertised to the peer: for example cipher suites and ECC curves.
In other cases it will abort the handshake: e.g DH parameters or the
peer key size.

Documentation to follow...

Conflicts:
	apps/s_server.c

Add callbacks supporting generation and retrieval of supplemental data entries, facilitating RFC 5878 (TLS auth extensions)
Removed prior audit proof logic - audit proof support was implemented using the generic TLS extension API
Tests exercising the new supplemental data registration and callback api can be found in ssltest.c.
Implemented changes to s_server and s_client to exercise supplemental data callbacks via the -auth argument, as well as additional flags to exercise supplemental data being sent only during renegotiation.

in order to prevent ssl3_get_record from never returning.

Reported by "oftc_must_be_destroyed" and George Kadianakis.

Contributed by Trevor Perrin.

Check for Suite B support using method flags instead of version numbers:
anything supporting TLS 1.2 cipher suites will also support Suite B.

Return an error if an attempt to use DTLS 1.0 is made in Suite B mode.

perform sanity checks on server certificate type as soon as it is received instead of waiting until server key exchange

possible to have different stores per SSL structure or one store in
the parent SSL_CTX. Include distint stores for certificate chain
verification and chain building. New ctrl SSL_CTRL_BUILD_CERT_CHAIN
to build and store a certificate chain in CERT structure: returing
an error if the chain cannot be built: this will allow applications
to test if a chain is correctly configured.

Note: if the CERT based stores are not set then the parent SSL_CTX
store is used to retain compatibility with existing behaviour.

is required by client or server. An application can decide which
certificate chain to present based on arbitrary criteria: for example
supported signature algorithms. Add very simple example to s_server.
This fixes many of the problems and restrictions of the existing client
certificate callback: for example you can now clear existing certificates
and specify the whole chain.

Only store encoded versions of peer and configured signature algorithms.
Determine shared signature algorithms and cache the result along with NID
equivalents of each algorithm.

Reviewed by: steve
Improved localisation of TLS extension handling and code tidy.

Move new structure fields to end of structures.

Fix encoding of use_srtp extension to be compliant with RFC5764

New function ssl_add_cert_chain which adds a certificate chain to
SSL internal BUF_MEM. Use this function in ssl3_output_cert_chain
and dtls1_output_cert_chain instead of partly duplicating code.

Submitted by: Robin Seggelmann <seggelmann@fh-muenster.de>
Reviewed by: steve

Support for TLS/DTLS heartbeats.

Make sure message is long enough for signature algorithms.

algorithms extension (including everything we support). Swicth to new
signature format where needed and relax ECC restrictions.

Not TLS v1.2 client certifcate support yet but client will handle case
where a certificate is requested and we don't have one.

OPENSSL_NO_SSL_INTERN all ssl related structures are opaque
and internals cannot be directly accessed. Many applications
will need some modification to support this and most likely some
additional functions added to OpenSSL.

The advantage of this option is that any application supporting
it will still be binary compatible if SSL structures change.